Heat exchangers of this kind are normally used as evaporators in air-conditioning devices for the interior compartment of vehicles. The pockets are each formed by two sheet-metal plates with recessed edge regions, the concavities of which face each other and are connected to each other, at their periphery, with a seal, the input and output chambers being delimited by areas of the recesses of greater depth than the remaining areas, such that, between two adjacent pockets of the said remaining areas, there is a gap for the passage of the second fluid in the lateral direction, the said openings being provided at the bases of the recesses, which are in mutual sealed contact around the openings. The two recesses of each pocket are furthermore connected with a seal in a central are of their breadth and over an appreciable portion of their length, starting from a first end rim, the two sides of the said U-shaped course extending on both sides of the said median area, such that the said areas of greater depth of the recesses are arranged adjacent to the said first end rim.
The object of the invention is to improve the operational characteristics of these evaporators.